Picture, up into transom top. I don't know what that metal elbow went to, it's thick so maybe an outboard diesel, yes they made them. I see marks where there might have been a small diesel in board. PS I like Capt. Ron and I have seen 3 pictures of my tank with gas in it. I believe this is the engine that was once here, A straight-three engine, also known as an inline-triple, or inline-three ... Detroit Diesel Series 71 and Series 53 engines were available in 3 cylinder form for .... configuration produces 803 pounds of thrust and pushes the boat to about 55 mph.